Photographic-print exposure-meter.



PATENTED APR. 25, 1905.

S. COHEN. PHOTOGRAPHIC PRINT EXPOSURE METER.

APPLICATION FILED JUNE 23, 1903.

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UNITED STATES Patented April 25, 1905.

PATENT OEEICE.

PHOTOGRAPHlC-PRNT EXPOSURE-METER.

SPECIFICATION forming part of Letters Patent No. 788,021, dated April25, 1905.

Application filed June 23,1903. Serial No. 162,802.

To al?, whom t may con/cern:

Be it known that I, SAMUEL COHEN, a citizen of the United States,residing at No. 1026 Market street, San Francisco, in the county of SanFrancisco and State of California,have invented certain new and usefulImprovements in Photographic-Print Exposure-Nieters; and I do herebydeclare the following to be a full, clear, and exact description of theinvention, such as will enable others skilled in the art to which itappertains to make and use the same.

My present invention is a photographicprint exposure-meter, which, asthe name signifies, is a device by the use of which the time required toperfectly print negatives of various degrees of density on develop-paperis accurately determined and the expense and time consumed in reachingthese results by the ordinary experimental method thereby obviated. Tobring the device to a finer degree of perfection, I have made itpossible to determine the time of exposures where different lights areemployed, and thereby increased the practical value and range ofusefulness of the device.

Other objects and advantages of the invention will appear in thefollowing description, and the novel features thereof will beparticularly pointed out in the claims.

The objects of my invention I am enabled to accomplish by the meansillustrated in the accompanying drawings, in which- Figure l is a frontelevation of the complete device. Fig. 2 is a section taken in thedirection of the line :c in Fig. l.

Referring now to the above views by letter, A represents asuitably-formed card bearing at its top a suitable heading and spacesfor notes and directions for use. Set into the card A in the mannershown in Fig. 2 and covering the perforations B, C, D, and E are thefilm-negatives F, G, H, and I, respectively, which increase in densityfrom F to I, which is the general range of results in every-dayphotography. Opposite each of these negatives is printed on the card alist of lights employed in this class of work, while adjacent negativehe compares it with the list of negatives on the card, and when he iindsits corresponding one in density he observes his light and exposes theprint the time set down in the table. To make matters more clear, saythat his negative corresponds in density to sample negative G and that acommon oillamp with a one-inch wick is used to print on special paper.The table indicates twelve seconds, which means that the print should beexposed twelve seconds in order to get good results.

A greater range of negatives, as well as a greater range of tables andlights, corresponding to standard papers can be employed; but in suchmatters, which lie within the spirit of my invention, I wish to beprotected.

What I claim, and desire to secure by Letters Patent, is-

l. A device of the class described, consisting of a frame having aseries of perforations arranged upon one side thereof in perpendicularalinement; a series of translucent negatives arranged over the saidperforations, said negatives being of different densities; and a seriesof print-exposure tables arranged in perpendicular alinement along theside of the frame opposite the disposition of said perforations, thetables being arranged with relation to corresponding negatives.

2. A device of the class described, consisting of a frame havingperforations therein; a series of translucent negatives arranged overthe perforations, said negatives being of different densities; and aseries of print-exposure tables arranged upon the frame, the tablesbeing arranged iixedly with relation to corresponding negatives.

In testimony whereof I affix my signature in presence of two witnesses.

SAMUEL COI-IEN.

Iitnesses GEORGE PATTISON, ELIZ. KINCAID.

